The feat is an effect applied by a cycling script - similar to the ioun stones if and when you try those out. The script checks for the conditions to apply the effect on a pretty short cycle as I recall.

There is a bug report here. I found it by searching with the keyword 'dashing'.

I've recently tried taking Dashing and Daring on a monk of mine (human, winged subtype), but the AC boost doesn't seem to happen at all.

Base AC is 17: is fully accounted for by: 4 dex, 2 wis, 1 tumble. A Charisma of 16 should be increasing it to 20.

Tried all combinations of shield/noshield, clothing/armor/naked. Tried relogging. Tested in combat and AC is indeed only 17; enter combat didn't seem to increase the displayed or actual AC at all, even in lengthy fights.

After combat, the skill bonuses trigger correctly, increasing the listed skills by +2 for some time (didn't time it exactly).

Any idea what else it might be? Has anyone else gotten the AC part of the feat to work at all in the past few years?